Major depression has been associated with both global and regional decreases in cerebral blood flow and glucose metabolism, assessed using emission tomography methods (reviewed in 1). In parallel, single voxel phosphorus-31 MRS has been used to document decreased levels of beta and total NTP in the basal ganglia (2; -16% and -6%) and the bilateral frontal lobes (3; -17% and -8%). Although these results are somewhat surprising, they are consistent with observations obtained from the cerebral cortex of polysubstance abusers (5; -10% and -7%) and decline in beta NTP in the basal ganglia of schizophrenics (4; -11%), disorders which have also been associated with sustained cerebral hypometabolism.
Over the last several years, van Zijl and colleagues (6,7,8) have clearly demonstrated that a .sup.1 H MRS resonance which arises from purines may be detected in the range 7.8-8.8 PPM using short echo times. This resonance arises primarily from adenosine phosphates, with a smaller contribution from NAA at 7.8-8.0 PPM.